Spark plug



S J. MASON Aug.I 12 1924.

SPARK PLUG Patented Aug. 12, 19.24,

UNITED STATES PATENT oFFicE.

STEWART J'. MASON, OF PORTLAND, OREGON, ASSIGNOR OF ONE-HALF TO EUGENE L. WIEDERMAN, F POIRTLANLD,.OREGON.

SPARK PLUG.

Application led Hay S1, 1921. Serial No. 473,731.

To all 'whom 'z't may concern:

Be it known that I, STEWART J. MASON,

a citizen of the United States, and a resident ofy the city of Portland, county of Multnomah, and State of Oregon, have invented a certain new and useful Improvement in Spark Plugs, of which the followin is a specification.

y invention relates generally to spark i0 plu s used in gas engines.

l invention relates particularly to spark-plugs provided with a heat coil for preheating the portion of the hydrocarbon vapors entering the spark plug, and thus producing) the necessary gasification, suit- Y able for eing ignited by the spark of the spark plug. The heating coil is considered a very desirable provision, but in any construction where the heating coil has contact with a porcelain core, the latter is apt to be cracked by sudden changes in `temperature, with the result that the spark plug as a whole is no longer fit for use.

My invention has for its object to provide a'spark plug including a heating coil so arranged as to be entirely free 9nd' independent of the core, thus only transmitting the heat thru a jacket of heated air sui'- rounding the core, hence tending to uniformly heat the latter.

It is further the object of my invention to provide simplicity of construction and accessibility to the arts. To this end I so arrange the parts o my spark-plug that the core may be readily removed and replaced without touching t e coil. Hence, in case of injury to the core all required is the putting in of a core in my spark-plug, without touching any other 40 The above specified an other'features are hereinafter fully described with referenceto the accompanying drawings, which? Fig. '1 is a side elevation gina sparkv plug embodying my invention.; Fig. 2 is a similar view with the shell of my spark plug shown -in vertical section4 so as to disclose the interior parts;

Fi 3 is a larger scaled vertical section of.

the s ell of my spark plug shown in Figs. 1 and 2 with the core omitted;

Fig. 4 'is a side elevation of different type of spark plug showing my invention applied thereto;

.-Fig. 5 is a vertical section of the shell art of the latter.

of the spark plug shown in Fig. fi; and

Fig. 6 is a larger scaled vertical section of the spark-plug shown in Figs. 4 and 5, with the core omitted.

Referring first to Figs. l to 3, these represent a spark-plug of approved type, in which a is the shell and b the core. The core shows a type of standard construction, being made with a porcelain or other insulating body, and an electrode c, the upper terminal connection of which is indicated by d. 4Said core is adapted to be securely affixed in the shell by the threaded portion e.

The shell a is metal and rcomprises an interior thread f adapted to receive the core, and an exterior thread g adapted to screw into the cylinder block. A hexagon portion L is adapted to accommodate a wrench. The shell is hollow or chambered, and in its `lower end has a ground electrode z'. A

hole istapped in the side ofrthe shell and a shouldered bushing y' is screwed into same. An insulating plug 7c is inserted in the bushing j, the insulating plu having a shoulder opposed to the shou der of the bushing. A binding st Z extends thru said insulating plug, the ead Z of said post being counter sunk in the inner face of the insulating plug c. The outer end of said binding post is threaded, and a terminal connection or nut m fitted thereon. A washer n of insulating material is preferably inserted between the terminal connection and the plug k. A resistance or heating coil o, is arranged within the open end of the chamber of the shell c, one of said coils being connected to the binding post Z in any convenient way, and the other end of such coil being ounded to the lower end of the shella. y referring to Figs. 3 and 5, it will be observed that the coil encircles the electrode d, but is spaced therefrom. Y

When the engine is being operated the sparking arrangement operates in the usual llectrical current is supplied-to the resistancecoil 0 as usual by a separate battery connection, not shown, by which the coil is heated to a high degree; and the coil functions as usual to vaporize the gas drawn into the cylinder, as is frequently required when first starting the engine.

In the event that the porcelain of the spark-plug .is cracked it is not necessary to discard the entire plug as is usually done now, but instead it 1s only necessary to put in a new core.

Figs. 1 to 3 inclusive represent the so called Splitdorf spark-plug.. As ordinarily made, this type of spark-plug has no heating coil as o, and my invention consists in providing a shell of this type of sparkplug with the heating coil constructed and arranged as above specified, and so as to be entirely free and independent of the core and electrodq carried by the latter.

In Figs. 4 to 6 inclusive the type of sparkplug here shown represents the standard Cham ion priming spark-plug. This spark-p ug likewise is not ordinarily made With a heating coil, and my invention consists in providing this type of spark-plug with a heating coil; and in doing so using substantially the same construction as shown in the preceding figures; the same parts added by invention being lettered in Figs. 4 to 6 inclusive'by the same letters as employed for like parts in Figs. l to 3 rnclusive. In the other parts as apparent, a rep` resents the shell, bf the core, g the exterior thread of the shell, c" the ground electrode, and o the electrode carried by the core.

The mode of securing the ends of the heating coil and the binding post and the shell is left to the mechanic. The details of construction shown in the drawings are merely those preferred by me.

I claim:

1. In a sparlr-plug of the character described, a shell, a core removably secured in one end of the shell, such core provided with one of the electrodes, the shell being provided with a hole located approximately midway between its ends, a bushing inserted in said hole," an insulating plug inserted in said bushing, a binding post secured in said insulating plug, and extending therethru into the interior of the shell, a heating coil having one end fastened to said binding post, and its opposite end grounded in the open end of the shell, said heat coil encircling the electrodecarried by the core but being spaced from said core .and its said electrode.

2. In a spark-plug of the character described, a shell, a core removably secured in one end of the shell, such core provided with one of the electrodes, the shell being provided with a hole located approximately midway between its ends, a bushing inserted in Said hole, an insulating plug inserted in SEIld bushing, a binding post secured in said insulating plug and extending therethru "into the interior-'0f the shell, the exteriorally 'projecting and of the binding post being adapted tohave one of the electric circuit wires attached thereto, and a heating coil vided withA a hole located approximately midway between its ends, a shouldered bushing inserted in said hole, an insulating shouldered plug inserted in said bushing, a binding post secured in said insulating plug, and extending therethru into the exterior of the shell, and a heating coil having one end fastened to said binding post, and its opposite end grounded in the open endof the shell, said heat coil encircling the electrode carried by the core but being spaced from said core and its said electrode,

4. In a spark-plug of the character described, a shell, a core removably secured in one end of the shell, such core provided with one of the electrodes,the shell being provided with a hole located approximately midway between its ends, a shouldered bushing inserted in said hole, an insulating shouldered plug inserted in said bushing, a binding post secured in said insulating plug, and extending therethru into the interior of the shell, the exteriorally projecting end of the binding post being adapted t0 have one of thel electric circuit Wires attached thereto, and a heating coil havin one end fastened to said binding post, an its opposite end grounded in the open end of the shell, said heat coil encircling the elec# trod@J carried by the core but being spaced from said core and its said electrode.

5. In a spark plug, a shell, a porcelain within said shell and having its lower end spaced inwardly for a substantial distance from thelower end thereof, a main electrode extending vertically of said porcelain and having its lower end terminating at a point slightly below the lower end of said shell, a second electrode extending radially inward from the lower end'of said shell and havingl its free end terminating in proximity to the lower end of said main electrode to form a spark gap therewith, an insulated binding post extending radially through the wall of the lower portion of said shell below the lower end of said porcelain, and a heating coil within the lower end ,of said shell and surrounding said main electrode in spaced relation thereto and to the lower end of said porcelain, said heating coil having one of its ends grounded to said shell and the other of its ends connecting said insulated binding post.

6. In a spark plug,

a shell, a porcelain body within said shell having its lower end spaced substantially midway the length of end of said porcelain body, said heating coil the shell, an electrode carried by the porceincluding a resistance wire around and lain body and having its end projectin spaced from the said electrode, one end of 10 through the space in said lshell and beyon said coil being attached to said shell, and a 5 the lower end thereof, a heating coil discontact member carried by said shell and posed wholly within the space between the connected to the %osite end of said coil. lower end of said shell and the adjacent S WART J. MASON. 

